WIP: checkpoint Wii native IMU and upstream IR bridge

Pause Wii pointing work with firmware 0.33-wii-trace installed. Preserve the pinned libogc IR pipeline, calibrated native IMU, software BOOTSEL, and standard camera sensitivity trial.

Tracking instability, tracking loss, and ineffective vertical movement remain unresolved. Level-2 camera filtering is not hardware-qualified. Nine targeted regression tests pass; firmware and persistent storage were verified after flashing.

tests/test_switch2_native_imu.py

@@ -0,0 +1,31 @@
+from __future__ import annotations
+
+import shutil
+import subprocess
+from pathlib import Path
+
+
+def test_switch2_native_imu(tmp_path: Path) -> None:
+    root = Path(__file__).resolve().parents[1]
+    compiler = shutil.which("c++") or shutil.which("g++")
+    assert compiler is not None, "a host C++ compiler is required"
+
+    executable = tmp_path / "switch2_native_imu_test"
+    subprocess.run(
+        [
+            compiler,
+            "-std=c++17",
+            "-Wall",
+            "-Wextra",
+            "-Werror",
+            "-pedantic",
+            f"-I{root / 'tools' / 'switch2_usb_probe'}",
+            str(root / "tests" / "switch2_native_imu_test.cpp"),
+            str(root / "tools" / "switch2_usb_probe" / "native_imu.cpp"),
+            "-o",
+            str(executable),
+        ],
+        check=True,
+        cwd=root,
+    )
+    subprocess.run([str(executable)], check=True, cwd=root)